Define “ground speed.”

Ground speed is defined as the speed of the aircraft relative to the Earth's surface. This measurement is crucial for pilots as it reflects how quickly the aircraft is moving across the ground. Understanding ground speed is essential for flight planning, navigation, and ensuring that the aircraft can safely reach its destination on time. It takes into account both the aircraft's airspeed and any effects of wind, such as headwinds or tailwinds.

It is important to differentiate ground speed from other types of speed, such as airspeed, which measures the speed of the aircraft relative to the atmosphere around it, not the ground below it. By focusing on the interaction with the Earth's surface, pilots can make informed decisions regarding their flight paths and estimated times of arrival.